The present invention relates to a tension- and moisture-proof and pressure-tight connection for electrical conductors such as in a conductor-to-conductor or conductor-to-terminal connection involving, for instance, mineral-insulated, metal jacket cables, tubular heaters, jacket type thermoelements and conductors with generally a high-temperature-resisting, synthetic insulation.
Electrical cables and conductors are connected and interconnected in various ways. For example, after two electrical conductors have been conductively interconnected, the joint is encased in a sleeve, and the interior of the sleeve casing not occupied by interconnected conductor portions is then filled with a suitable filler, such as a heat-curable or a self-cross-linking casting resin which bonds the sleeve, the conductors, and insulation together. A problem exists hereby that the filler is difficult to inject without inclusion of air bubbles which are detrimental to the mechanical strength of the connection.
Generally speaking, certain materials are used as jackets and/or insulation envelopes; for instance, polyethylene or copolymers of ethylene, or polyvinylchloride are commonly used for this purpose. These materials are also adequate in many cases for obtaining a sufficiently strong bond with other parts. The situation is different for electric conductors or cables operating at high temperatures, such as insulated heating conductors. In this case, one uses polyolefines containing fluoro as insulation. These insulations are difficult to be mechanically connected to other parts in a sufficiently strong and tight manner.
The problem above has been approached by attempting to improve the anti-adhesiveness of, e.g., polytetrafluorethylene, e.g., by means of a surface treatment; but this approach was not successful. Thus, sleeve- and fitting-like connections between two such heating conductors have been made in the past through the use of sleeves made of the same material as the insulation and under utilization of screw connections cooperating with sealing elements. The latter, however, posed problems and moisture may penetrate through and into the connection. Not only does ingress of water interfer with the electrical operation, but it may also destroy the connecting sleeve entirely. Moreover, in explosionproof rooms, only unreleasable sleeve connections are permitted.